"An assessment of the per-well productivity for the Olympic Dam Geothermal Energy Project, estimates the net power capacity of each production well could be as high as 7.6 megawatts of electricity," Green Rock said.

The assessment was based on conditions in the hot granites in the company's Blanche-1 exploration well, drilled to 1.93km depth near BHP Billiton’s Olympic Dam copper and uranium mine.

"The results of the assessment undertaken by GeothermEx, a major United States-based international geothermal consulting company, together with the large area of prospective hot granites known from previous drilling, confirms the enormous potential of this engineered geothermal project," Green Rock said.

"This assessment follows on from the recently completed tectonic analyses undertaken at the Blanche-1 well by the CSIRO which confirmed the stress regime in the Olympic Dam hot granites is likely to be ideal for generating an optimal heat exchange reservoir."

The next step in Green Rock's evaluation process will be a mini hydro-fracture in Blanche-1 to measure the magnitude of principal stress directions.

The company said the data from this mini-frac would be used in preparation for drilling deep geothermal wells and designing a fracture stimulation program to establish an engineered underground reservoir connecting the wells.

The mini-frac is planned for the last quarter of this year.

The Olympic Dam Geothermal Energy Project, wholly owned by Green Rock Energy, is in South Australia within 10km of the Olympic Dam mine and 5km from one 275kV and one 132kV power transmission line connected to the Eastern Australian power grid.

Green Rock is evaluating an artificial geothermal system and associated pilot power plant at Olympic Dam prior to constructing engineered geothermal reservoirs to provide heat energy for a large baseload power plant with a capacity in excess of 400 MW.